Your files stay on your Mac.
AIFF (Audio Interchange File Format) is Apple's uncompressed audio container, used in professional audio workflows and music production. Convertessa reads your .aiff files and converts them to 13 output formats — AAC, MP3, FLAC, WAV, OGG, and more — entirely on your Mac. No upload, no internet connection required.
Drag a single .aiff file or an entire folder into Convertessa. You can also pass files via the command line.
Pick a format from the output list — AAC, FLAC, MP3, WAV, or any of the 13 supported targets.
Click Convert. Convertessa writes the output files to your chosen folder. Everything runs locally — files never leave your Mac.
Images, audio, video, documents, archives and eBooks — all converted natively, right on your Mac.
Pick a format you have — see everything Convertessa can turn it into.
Convert hundreds of files at once with per-type group defaults and individual overrides.
First-class support for HEIC, AVIF and WebP — encode and decode, both ways. Read JPEG XL and a dozen more modern formats too.
Drop files anywhere on the window. Native, instant, and exactly what you’d expect on a Mac.
Dial in compression, resolution and bitrate. Keep originals pristine or shrink for sharing.
Never overwrite a file by accident. Convertessa appends safe suffixes automatically.
Every job is logged locally. Re-run a previous conversion or revisit recent outputs in a click.
Bundle your converted files straight into a single ZIP, TAR or 7z — packaged and ready to share the moment a job finishes.
Right-click any file in Finder and choose Convert. A Quick Action handles it on the spot — no need to open the app first.
Shrink Convertessa to a tidy mini window that tucks into a corner — just a drop zone and a format picker for quick, one-off conversions.
No cloud. No account. No upload. Every conversion happens entirely on-device, using the power already in your Mac. What you convert is nobody’s business but yours.
Script conversions, wire them into your build, or batch a folder from the terminal. The same engine, no GUI required.
Read the full CLI documentation →Shrink Convertessa down to a small, focused window — drop, convert, done, with your recent conversions one click away.
macOS 14+ · Apple Silicon & Intel
New formats, new features, and fixes — every release, on the record.
It depends on the target format. AIFF is uncompressed, so converting to another lossless format — FLAC, WAV, AU — preserves the original audio data exactly. Converting to a lossy format such as MP3, AAC, or OGG does reduce quality, which is a property of those formats, not of Convertessa.
Yes. Drop a folder onto Convertessa or run convertessa *.aiff --to flac from the command line. All .aiff files are converted in one pass.
No. Convertessa runs entirely on your Mac. Your audio files are never sent to any server.